Checking The Surface Potential Control System - Canon iR105 Service Manual

2.7.11 Checking the Surface Potential Control System

a. Outline
If image faults occur, it is important to find out whether the cause is in the latent static im-
age formation block (including the photosensitive drum and the potential control system) or
it is in the developing/transfer system, requiring a check on the surface potential. (You can
check the surface potential in service mode.)
b. Disabling the Auto Control Mechanisms
As a way of checking the mechanisms used for corona current control, lamp intensity
control, or developing bias control, you may disable the auto control mechanisms (hereafter,
non-auto control mode).
As a first-aid measure when a fault exists in the auto control mechanism, you may use
non-auto control mode; keep in mind that all outputs in non-auto control mode are fixed to
standard values.
1. Procedure
1) Make the following selections in service mode, and enter '0':
COPIER>OPTION>BODY>PO-CNT.
2) Press the Reset key twice.
In non-auto control mode, all settings used for coronal current control, in-
tensity control, developing bias control will be set to standard settings
stored in ROM.
2. Making Use of Non-Auto Control Mode
If a fault occurs in images, use the mode to find out if the cause is on the input side or
output side of the microprocessor on the DC controller PCB.
In non-auto control mode, if the fault is corrected somewhat, you may suspect the poten-
tial measurement unit or the DC controller PCB.
COPYRIGHT© 2001 CANON INC. 2000 2000 2000 2000 CANON iR105 REV.0 JULY 2001
CHAPTER 6 TROUBLESHOOTING
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